The invention relates to a waveguide optical semiconductor device, a method of fabricating the same and an optical device module.
A conventional waveguide optical semiconductor device is described, for example, in Proceedings of the 1993 Conference of the Institute of Electronics, Information and Engineers, p. 4-195. A waveguide optical semiconductor device described in this publication includes a waveguide portion and an upper electrode disposed on the waveguide portion.
In a conventional waveguide optical device, the waveguide portion sticks out of the surface of the device. Therefore, in manufacturing or inspecting the device, external force tends to be applied to the waveguide portion. As a result, cracks or defects are generated in the upper electrode or the waveguide portion.
A conventional optical device module is described, for example, in Proceedings of the 1997 Conference of the Institute of Electronics, Information and Engineers, p. 347. An optical device module described in this publication includes a waveguide optical semiconductor device and a carrier on which the optical device is mounted.
In a conventional optical device module, the carrier has terrace-shaped SiO2 films on its surface for receiving the optical device. The SiO2 films are swellings in the device mounting region of the carrier. Therefore, levelness of the device mounting region is reduced.
It is therefore an object of the invention to provide a waveguide optical semiconductor device, a method of fabricating the same and an optical device module, which solve the above-described problem. According to the present invention, such a device includes a substrate, a waveguide formed on the substrate, an electrode layer formed on the waveguide, and bumpers formed on the substrate, the bumpers are disposed on both side of the waveguide, and top surfaces of the bumpers are higher than a top surface of the electrode layer.
Therefore, the electrode layer formed on the waveguide does not stick out of the top surface of the bumpers. As a result, it is avoided that external force is applied to the waveguide.